US4990760A
Expired / Lapsed
US
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IC card having means for protecting erroneous operation
Assignee: Lapis Semiconductor Co Ltd
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Filing: 1989-05-04
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Granted: 1991-02-05
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Expires: 2009-05-04
Abstract
Abstract An IC card having means for protecting erroneous operation. A circuit for detecting incomplete contact is provided.
Inventors
- 👤 Nobuhiro Tomari
- 👤 Kougi Tanagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:36
CPC Classifications
G; G06; G06K; G06K19/00; G06K19/06; G06K19/067; G06K19/07; G06K19/0701; G06K19/073
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
141 words
An IC card having means for protecting erroneous operation comprising: a plastic card having a plurality of terminal pads located on the surface thereof, said plurality of terminal pads including a positive power supply terminal pad, a ground terminal pad, a resetsignal input terminal pad, and a clock signal input terminal pad; an IC chip locating in said plastic IC card and being connected to said plurality of terminal pads; a potential reducing circuit connected between said positive power supply terminal pad and said resetterminal pad; and means for protecting erroneous operation of said IC chip comprising a first circuit for detecting incomplete contact between said power supply terminal pad and an external devise to output a detecting signal, and a second circuit for generating a reset signal to stop operation of said IC chip in response to said detecting signal.
Claim 2
Dependent Claim
141 words
An IC card having means for protecting erroneous operation comprising: a plastic card having a plurality of terminal pads located on the surface thereof, said plurality of terminal pads including a positive power supply terminal pad, a ground terminal pad, a resetsignal input terminal pad, and a clock signal input terminal pad; an IC chip locating in said plastic IC card and being connected to said plurality of terminal pads; a potential reducing circuit connected between said positive power supply terminal pad and said resetterminal pad; and means for protecting erroneous operation of said IC chip comprising a first circuit for detecting incomplete contact between said power supply terminal pad and an external devise to output a detecting signal, and a second circuit for generating a reset signal to stop operation of said IC chip in response to said detecting signal.
Claim 3
Dependent Claim
50 words
An IC card according to claim 1, wherein the said first circuit has a transistor having a gate electrode receiving a potential on said power supply terminal pad, a source electrode connected to said resetsignal input terminal pad, a drain electrode connected to an input of said reset signal generator.
Claim 4
Dependent Claim
81 words
An IC card according to claim 1, wherein said first circuit has a resistive potential divider connected between said positive power supply terminal pad and said ground terminal pad to produce a divided potential, and a transistor having a gate electrode receiving said divided potential, a drain electrode connected to said power supply terminal pad through a resistor and connected to an input of said resetsignal input terminal pad, and a source electrode connected to said clock signal input terminal pad.
Claim 5
Dependent Claim
131 words
An IC card according to claim 1, wherein the said detector for said positive power supply terminal pad and said first circuit has a transistor having a gate electrode receiving a potential on said power supply terminal pad, a source electrode connected to said resetsignal input terminal pad, a drain electrode connected to an input of said reset signal generator, and has a resistive potential divider connected between said positive power supply terminal pad and said ground terminal pad to produce a divided potential, and a transistor having a gate electrode receiving said divided potential, a drain electrode connected to said power supply terminal pad through a resistor and connected to an input of said resetsignal input terminal pad, and a source electrode connected to said clock signal input terminal pad.
Claim 6
Dependent Claim
20 words
An IC card according to claim 1, wherein said the potential reducing circuit comprises a plurality of diodes serially connected.
Claim 7
Dependent Claim
15 words
An IC card according to claim 1, wherein said second circuit comprises a flip-flop circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-04 | 1994-08-06 | 1995-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-04 | 1998-08-06 | 1999-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-04 | 2002-08-06 | 2003-02-05 | $7700.00 | Window Closed / Lapsed |